Major brands are, as a group, offering trusted products. Many differ with the form of the vitamin or mineral in addition to the fillers, if used, that may cause a reaction. ConsumerLab offers product testing in addition to indepth information you can utilize to increase your nutritional knowledge.

jgalello, I want to return to finish answering your question as I had an interruption. I like Bestvite's Benfotiamine because of minimal fillers and I favor liposomal vitamin C because it lasts longer, offers better absorption and protects against vitamin C irritation. Liposomal delivery increases absorption levels that otherwise would be ineffective. Curcumin is a good example. I also like olive leaf extract by East Park. Dosage is an individual matter depending if it's for maintenance or a health issue in addition to other factors such as weight and age. You would benefit consulting a health care professional for the best levels to use as a Herxheimer or Die-Off symptoms could result from using high levels too soon.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6714268/
https://www.sciencedirect.com/science/article/abs/pii/S0308814612001744
https://www.thecandidadiet.com/olive-leaf-extract/